<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>排他思想</title>
</head>
<body>
    <button>按钮1</button>
    <button>按钮2</button>
    <button>按钮3</button>
    <button>按钮4</button>
    <button>按钮5</button>
    <script>
        // 排他思想
        var btns = document.getElementsByTagName('button')
        for (var i = 0; i < btns.length ; i++ ) {
            btns[i].onclick=function() {
                // 先排除其他按钮的背景颜色 干掉其他人
                for (var i = 0; i < btns.length ; i++ ) {
                    btns[i].style.backgroundColor=''
                }
                // 在把点击按钮的背景颜色修改  留下自己
                this.style.backgroundColor='pink';
            }
        }
    </script>
</body>
</html>